Slowness tester for paper stock



Dec. 29, 1931. G. F. FRENCH SLOWNESS TESTER FOR PAPER STOCK Filed May 19, 1951 ATTORNEY l N VEN TOR.4

Patented Dec. 29, 1931 l uNrrlszov sTxri-:sl PATENT oFFlcE GEORGE F. FRENCH, OF STAMFORD,

CONNECTICUT, ASSIGNOR T0 RIEGEL PAPER COR- PORATION, OF RIEGELSVILLE, NEW JERSEY, A CORPORATION F NEW JERSEY 7 sLowNEss TESTER Application led May 19,

This invention relates to apparatus for testing the slowness of the`paper stock which paper, the stock is beaten outand hydrated. As hydration proceeds, the stock tends to gifve up its water less and less freely, as on the drainagewire of the paper machine for, instance. Hence, a stock which has been hydrated to a comparatively low degree and so gives up its water more or less freely is known as free, while a stock in which hydration has been developed toY a high degree is known as slow.

The slowness of the paper stock is of prime importance, since on it largely depend not only the physical properties of thepaper made'therefrom but also the speed" at which the paper machine can properly be run.y v For example, other things being equal, the slower the stock the greater will vbe the bursting strength and the smoother will be the finish of the paper; and if the stock is too slow on the wire of the machine it will necessarilygo very wet to the presses, with the result that the paper may crush, cockle, or be too dense, too low in strength, or too tinny or brittle. In any event, uniformity in the quality of the finished paper cannot be obtained without uniformity in the slowness of the stock.

The present standard practice in testing the slowness of paper stock is substantially as follows: A sample of the stock is obtained and, as the results from the apparatus employed are very much affected by consistency, is lirst subjected to a preliminary consistency test-ordinarily by weighing a small portion of the sample, bone-drying it, weighing the` dry residue, and then adding to the main part of the sample water sufficient to give it a standard thin consistency of say 0.3 per cent., i. e., 0.3 per cent. of fiber to 99.7 per cent. of water. A -measured portion of the sample thus prepared, usually a liter, is then provide a simple, elicient, and

` glass, but as the drainage Eon PAPER s'rocx 1931. serial No. 535,599.

placed in a container having a bottom of wire mesh which is mounted over a funnel-shaped receptacle provided with a small orifice in its bottom and a larger orifice in one side somewhat above the bottom. The water in the sample drains through the strainer bottom of the container while the fibers therein are deposited and form a mat thereon, the rate of drainage, dependent on the slowness of the stock, being comparativelyrapid at irst but decreasing as the head of the stock in the oontainer lowersand the thickness of the mat of deposited fibers increases. As the water drains from the container into the funnel below, it cannot all flow through the restricted orifice in the bottom of the latter during the initial rapid drainage but backs up therein and runs out through the side orifice, whence it is conducted into a graduated measuring slows up the bottom orifice shortly becomes sullficient therefor and the water in the funnel then sinks below and ceases tolflow through the side orilice. The amount of the overflow water collected in the measuring glass thus measures the slowness of the stock. For example, with a very free stock such as an unbeaten sulphite pulp, the measuring glass will receive about 700 of the 1000 cubic centimeters of the sample used in the test, and as the hydration of the stock is developed lower Iand lower readings will be obtained thereinuntil, carried to an extreme vas in thecase of stock for glassine paper, the measuring tube will receive only 20 to 30 cubic centimeters of the overflow water. The slowness test is usually run twice from the prepared dilute sample, between and after which the apparatus .has to be thoroughly washed and rinsed. A slowness test as outlined usually takes from twenty to twenty-five minutes, including the determination of consistency.

By my presentinvention I have provided .an apparatus which, while certain of its parts may bey manipulated to make tests whenever and as often as desired, in its entirety is automatic in its operation and will accurately make and record slowness tests in-a continuous seriesand at regular short intervals, say every three minutes. f

One practical embodiment of the invention is shown, by way of illustration and not of limitation, in the accompanying drawings, in which- Figure 1 is a more or less diagrammatic View showing the apparatus partly in elevation and partly in vertical section and the mechanism and electric circuits by which its valves are automatically controlled; Fig. 2 is the face view of a portion of a chart on which a series of slowness tests has been recorded.

Paper stock, usually of a fairly thick cousistency#in the neighborhood, say, of 2 to 3 per centr-is ordinarily fed tothe paper machine through a stuff gate into a stream of white water, which is the drainage water recirculated from the paper machine, and the resultant stock, thus thinned to a consistency, usually, of 0.3 to 0.8 per cent. generally depending upon the kind of paper to be made, passes through riiiiers and thence by gravity to the Screens, in many mills located from three to four feet below the riiiiers, and from the screens flows directly to the paper machine. l

The apparatus, which as shown comprises as its principal parts a wire-head A, standpipe B, recording pressure-gauge C. showerhead D, and catch-bowl E, will usually be installed in a convenient position generally adjacent to the riftlers and screens and con-y nected therewith, to receive a flow of the diluted stock from the bottom of the riillers, since I have found that the apparatus, unlike the old testers described. is not very sensitive to consistency variation and that the accuracy of the slowness tests as made and recorded thereby is not seriously affected by any ordinary variations in the consistency of the stock in the rifHers.

The wire-head A consists of a. chamber 1, with a strainer-head or top 2 of wire mesh. which may be strengthened, if found desirable, by a b acking'of heavier and coarser wire mesh (not shown) preferably so applied to the upper side of the head that no fibers will be caught between the two sets of wire mesh. The upper end of the wire-head is surrounded by a collecting` cup 3, which discharges at one side into the open head of the stand-pipe B; and at its lower funnel-shaped end is connected by a pipe 4, controlled by an inletvalve 5 and preferably equipped with a thermometer 6 to register the temperature ofthe stock therein, to a T-conneetion the upper end 7 of which is connected to the bottom of the riiiiers and the lower end 8 to the screens. and is also connected by a pipe 9, controlled by a drainage-valve 10, with the catch-bowl E. Thus, when the mill is in operation. a steady stream of diluted paper stock will How from the riiiers through the T-conncction and thence either to the screens or, when the inletvalve 5 is open, in part at least to the wirehead which, it is to be understood, is located at a level suliiciently below that of the screens to provide the desired pressure of the stock within the wire-head. The connections shown provide a constant circulation of the stock, which it is well to have, and avoids the necessity for a pump with which to pump the stock from the lower branch of the T-conncction back, say, into the riiiler box.

The stand-pipe B has at its lower end an outlet-pipe 11, which is controlled by a drainage-valve 12 and discharges into the catch-bowl below, and, preferably also as shown, a pipe 13 of small diameter which provides a restricted drainage outlet.

The pressure recorder C, which is or may be a liquid-level gauge of standard type, comprises as usual a pressure-pipe 14 the mouth of which is here located within the standpipe adjacent its lower end, and a pivoted arm 15 carrying a pen adapted to bear on the face of a rotating paper chart 16. For some paper stocks, the mouth of the pressure tube may be equipped with a standard diaphragm box (not shown) provided with a fine rubber diaphragm, to prevent any possible clogging of the pipe by fine fibers which may pass through the wire-head and into the standpipe.

The shower-head D, here provided with an additional enlarged spray opening 17 directly over the center of the wire-head A, has a water supply-pipe 18 which is controlled by an inlet-valve 19 and, preferably, is also equipped with a dri p-pipe 2O so located as to drain into the catch-bowl the upwardly inclined end of the supply-pipe and any water which may leak through the valve when closed. And to provide for the rapid drainage of the shower-head when the water is shut off at the valve, it is equipped at the top with an air inlet-pipe 21 controlled by a check-valve The catch-bowl E has an outlet-pipe 23 in its funnel-shaped bottom which discharges to the sewer or, if desired, to some recovery system.

The control valves 5, 10, 1Q, and 19, preferably of a quick-acting type, are electromagnetically actuated. The normally closed inlet-valve 5 is opened by a solenoid s against the action of a closing spring, while the drainage-valves 1() and 12, which are normally open, are closed by the solenoids s1 and S12, respectively, against the action of opening springs, or the action of the solenoids and the springs may be reversed if desired; and, when these three valves are to be actuated simultaneously, the coils of their actuating solenoids are connected across suitable feedwires m and y either in series or, preferably as shown, in parallel by the common circuit wires a and 7), controlled by a switch m, a mercury switch as shown, and thence, respectively, by the wires c and d, e and f, and g and L. The water inlet-valve 19, normally closed, is opened by a solenoid s1", against the action of a closing spring, a separate circuit for which is provided by the Wires j and controlled by a second mercury switch n.

The two cont-rol switches are in turn controlled by a timing device comprising the two cams o and p which are mounted to rotate together at slow speed, as upon a shaft driven bya motor through reducing gears or from some suitable part of the paper machine. These cams are so shaped and relatively positioned that, on each revolution, the active face of the cam 0 will first tilt the switch m, to close the actuating. circuits of the valves 5, 10 and 12, tion for a time, and then, its active face passing from .engagement therewith, allow the switch to drop to and remain in open position, and, at a short interval after-the switch m has dropped face of the cam tilt the switch n, to close the actuating circuit of the valve 19, hold it in closed position for a time, and then pass by and allow the switch to drop to and remain in open position.

The operation lows: Starting with the' control cams o and p in the positions shown in the drawings, the switches 7n, and n are open, the actuating solenoids of all the valves are fle-energized, and the two inlet-valves 5 and 19 are closed while the two drainage-valves 10 and 12 are open. As the cams rotate, the switch m is first engaged and tilted to closed position, closing and so energizing the circuits of the solenoids S5 81 S12 which respectively open the inletvalve4 5 and close the drainage-valves 10 and 12 and hold them in such position so long as the solenoid actuating circuits remain closed by the switch m. Thereupon, the stream of thin paper stock in the pipe 7 flows therefrom through the pipe 4 and thence, the valve 10 being closed, upwardly into the wire-head, and, the. chamber quickly filling, is forced under a constant and considerable pressure against the wire mesh strainer. of the stock collect and form a maton the lower surface of the stramier, while the water passes through into the collecting cup and thence runs down into the stand-pipe, comparatively rapidly at first and more and more slowly as the ber mat increases in thickness. The water thus disch/arged into the standpipe drains ofi" through the restricted outlet provided by the pipe 13; but, as this outlet is too small to carry it all off during the initial rush, the water will first rise in the pipe to a maximum level which, dependent upon the rate of drainage in turn dependent upon the slowness of the stock as hereinabove explained, through t-he pressure created thereby in thetube 14 will be recorded on the paper chart by the outward swing of the arm 15, and then, as the discharge slows up and falls below the drainage capacity of the pipe vdrainage-pipe 13 may,

hold it in closed posi-J into the stand-pipe will to open position, the active, p will similarly engage and of the apparatus is vas fol- The fibers j 13, the level of the water in the stand-pipe drops and so reducesthe pressure inthe pipe of the recorder until, usually on the opening of the drainage-valve 12, it sinks below the level of the mouth of so removes all pressure therein. The heavy outerlends of the lines 16a recorded on the chart v(see Fig. 2)'mark the drop in pressure due to the lowering of the level lof the water in the stand-pipe from its level from which the stand-pipe is rapidly drained by the opening of the valve 12. The however, be omitted, thev water discharged continue to rise therethe chart, so long as and if so the level of in, and be recorded on the discharge from the and the valve 12 remains closed,-but will fall rapidly when this valve 'is openedl to drain the stand-pipe. After a period determined by the timing device, the circu-its of the valveactuating solenoids are broken' at the switch mand thereupon the inlet-valve 5 is closed and the two drainage-valves 10 and 12 are opened by their springs, thus shutting off the flow ofthe stock to the apparatus and draining both' the wire-head and the stand-pi, e.

the pressure tube and maximum to the y Then, after a brief interval, the cam p ti ts up theswitch 'n to close the actuating circuit of and so energize the solenoid of the water inlet-valve 19, which is thereupon opened and remains open until its actuating circuit is broken at the switch n, While the valve 19 is open water flows through the supply pipe into the shower-head and, closing the checkvalve 22, is projected downwardly, through the opening 17 in a heavy stream which will break the fiber matformed on the under side of the screen of the wire-head centrally, and through the surrounding spray-holes in finer jets whichwill complete the breaking up of the fiber mat and will thoroughly wash out the wire-head, the collecting-cup, and the stand-pipe; and, when the water is shut off on the closure of the` valve 19, the check-valve '22 will open to admit air'to the shower-head the two drainage-valves remain open for a period, allowing the apparatus to drain thoroughly, and then the above-described cycle of operations is repeated.

. The apparatus may be adapted for measuring and recording stock of a wide range of slowness in various ways-for instance, by raising or lowering the elevation of the wirehead, thus varying the pressure on the screen 'of the stock flowing thereto, by making thewire-heads of different diameters, and using the larger heads with the greater drainage area for slow-stocks, by increasing or diminishing the diameter of the stand-pipe and pipe some two feet in height and two and onehalf inches in diameter, with a discharge outlet of one-eighth inch diameter in the pipe 13, give good results. In case the pipe 13 is omitted, the stand-pipe should be of somewhat larger diameter so as to give it a capacity to take all the water discharged from the wire-head without unduly raising the pressure on the pressure recorder. It is essential, however, that the amount of wash water discharged through the shower-head be so adjusted with reference to the capacity of the stand-pipe that the rise thereof in the stand-pipe shall not appreciably affect the pressure recorder, as otherwise the recording pen might be swung out further than during the slowness tests and so destroy the readings for such tests. Also, while the timing of the control for the valves may be widely varied, I have found that very satisfactory results can be obtained by driving the control cams at a speed of one revolution per three minutes, giving the active faces of these cams arcs of 900 and 60, respectively, and so posivtioning th-e cam 7) with respect to the cam 0 that its active face will engage and close the switch n at an interval of from one to five seconds after the active face of the canr 0 has passed from the switch m and allowed that switch to open. Thus, a slowness test of the paper stock will be recorded onvthe chart every three minutes, that is to say, twenty tests per hour; and, during each three minute period, the actuating solenoids of the valves 5, 10 and 12 will be energized for forty-five seconds, the actuating solenoid of the valve 19 will, after a very brief interval,

be energized for thirty seconds, and then the actuating solenoids of all four valves will be deenergized for the remainder of the period, or about one hundred seconds.

In certain cases, as for use in mills where the screens are at a comparatively low elevation, it may be desirable to place the flow of the paper stock to the wire-head under full rifiier pressure, which can readily be done by inserting in the pipe 8 a normally open valve similar to the valves 10 and 12 and connecting the coil of its actuating solenoid in parallel with the solenoids of these valves and the valve 5. Also, on certain highly hydrated stocks, such as glassine, where the bers tend to cling quite tenaciously to the strainer ofthe wire-head, the shower-head may be connected with its water supply-pipe by a short length of rubber hose and mounted to oscillate slightly, or to rotate back and forth through a short arc, to more surely break off and wash out all the matted fibers.

Vhile I have shown and describeda complete automatic slowiness recording apparatus in what l now consider to be the best embodiment of the several parts thereof, it is to be understood that handpperated valves may be substituted if automatic operation is not desired, and that the parts of the appara tus may be further modified in their details, or certain of the parts omitted entirely, within the scope of the appended claims, without departing from the spirit or sacrificing the advantages of the invention.

What I claim as new, and desire to obtain by Letters Patent, is#- 1. Apparatus of the type described comprising a wire-head, means for supplying during a predetermined time interval a stream of dilute paper stock to the under side of the strainer of the wire-head under constant pressure, and means for measuring the discharge from the wire-head during such time interval.

2. Apparatus of the type described comprising a wire-head, means for supplying during a predetermined time interval a stream of dilute paper stock to the under side of the strainer of the wire-head under constant pressure, and means for measuring the discharge from the wire-head during such time interval in excess of the capacity of a restricted drainage outlet.

3. Apparatus of the type described comprising a wire-head, means for supplying to the under side of the strainer of the wirehead during a predetermined time interval and under a constant head a dilute paper stock from a stream thereof flowing from the rifiiers of a paper mill, and means for measuring the discharge from the wire-head during such time interval.

4. Apparatus of the type described comprising a wire-head, means for supplying to the under side of the strainer of the wirehead during a predetermined time interval and under a constant head a dilute paper stock from a stream thereof flowing from the riffiers of a paper mill, and means for meas uring the discharge from the wire-head during such time interval in excess of the capacity of a restricted drainage outlet.

5. Apparatus of the type described comprising a wire-head, means for supplying for a predetermined time interval a stream of dilute paper stock to the under side of the strainer of the wire-head under constant pressure, means for measuring the discharge from the wire-head during such time interval, means for draining the wire-head, and means for supplying a shower of water to break off the fiber mat formed on the under side of the screen of and to wash out the wire-head.

6. Apparatus of the type described comprising a wire-head, means for supplying for a predetermined time interval a stream of dilute paper stock to the under side of the water to break off the strainer of the wire-head under constant pressure, means for. measuring the discharge from the Wire-head during such time interval in excess of the capacity of a restricted drainage outlet, means for draining the. Wirehead, and means for supplying :a vshower of liber mat formed on the under side of the screen of and to Wash out the wire-head.

7. Apparatus of the type described comprising a Wire-head, means for supplying during a predetermined time interval a stream of dilute paper stock to the wire-head under constant pressure, a receiving vessel adapted to receive the discharge from the wire-head, and means for measuring the level to which the discharge from the wirehead rises in the receiving lvessel during such interval.

8. Apparatus of the type described comprising a wire-head, means for supplying during a predetermined time interval a stream of dilute paper stock to the wirehead under constant pressure, a receiving vessel adapted to receive the discharge from the wire-head and having in its bottom a restricted drainage outlet, and means for measuring the level to which the discharge from the wire-head rises in the receiving Avessel during such interval.

9. Apparatus of the type described, comprising a wire-head, means for supplying during a predetermined time interval a stream of dilute paper stock to the wire-head under constant pressure, a receiving vessel adapted to receive'the discharge from the wire-head, and associated with the receiving vessel a pressure gauge adapted to record the level to which' the discharge from the wirehead rises in the receiving vessel during such interval.

10. `Apparatus of the type described comprising a wire-head, valve-controlled means for introducing into the wire-head under constant pressure a stream of dilute paper stock flowing from the riliclers of the paper mill, a

receiving vessel adapted to receive the disf charge from the wire-head, a pressure recorder associated with the receiving vessel adapted to record the maximum level to which the discharge from the wire-head rises in the receiving vessel, means for draining both the wire-head and the receiving vessel, and a shower-head for supplying a shower of lwater to break off the fiber mat formed within the wire-head and to wash out both the wire-head and the receiving vessel.

11. Apparatus of the type described comprising, in combination, a wire-head having valve-controlled inlet and drainage orifices, means for supplying a stream of dilute paper stock under constant pressure to the inlet orifice of the wire-head, a stand-pipe located adjoining and adapted to receive the discharge from the wire-head and .having a valve-controlled drainage orifice, a recording pressure-gauge operatively associated with the stand-pipe to record the maximum level to which the discharge from the wire-head rises in the stand-pipe during a predetermined time interval, and a shower-head having a valve-controlled water supply-pipe mounted over and adapted tok direct a shower of water down upon the wire-head.

12. Apparatus of the type described comprising a wire-head having valve-controlled inlet and drainage orices, means for supplying a stream of dilute paper stock under constant pressure to the inlet orifice of the wirehead, a collecting cup surrounding the upper end of the wire-head, a stand-pipe having a valve-controlled drainage orifice located adjoining the drain-pipe to receive from the collecting cup the discharge from the wirehead, a recording pressure gauge operatively 35 associated with the stand-pipe, and a showerhead having a valve-controlled water supplypipe mounted directly over the wire-head and collecting cup.

v 18. Apparatus of the type described comprising, in combination, a wire-head havin a valve-controlled inlet-pipe adapted to be connected with a pipe through which a stream of dilute paper stock constantly flows from the riilers of a paper mill, whereby such paper stock may be admitted to the wire-head under pressure when the valve is open, and also7 having a valve-controlled drainage-pipe, a stand-pipe located to one side of and somewhat below the wire-head and having a valve- 10. controlled drainage-pipe, a collecting-cupI surrounding the wire-head adapted to receive the discharge therefrom and conduct it into the stand-pipe, a pressure-gauge operatively associated with the stand-pipe, and a show'er- 105 -head with valve-controlled water inlet-controlled water inlet-pipe located over the wire- Vhead and collecting-cup and having in addition to the usual spray-holes therein a larger opening substantially over the center of the wire-head. v

14. Apparatus of the type described comprising, in combination, a wire-head having inlet and drainageoriices, a stand-pipe adapted to receive the discharge from the wire-head and having a drainage orifice, a pressure recorder operatively associated with the stand-pipe, 'a shower-head adapted to wash out the wire-head a-nd stand-pipe and having a water inlet orifice, automatically actuated valves ,controlling said orifices of the wire-head, stand-pipe and shower-head, and timing means for controlling the actuation of said valves whereby during successive predetermined time intervals the valve controlling the inlet orifice of the wire-head Will be open and the valves controlling the drainage orifices of the wire-head and stand-pipe will be closed for a substantial fraction of each time interval and will be closed and open respectively during the remainder thereof and shortly after the closure of the said inlet valve and opening of the said drainage valves the valve controlling the water inlet oriice of the shower-head will be open for another substantial fraction of such time interval and will be closed during the remainder thereol.

l5. Apparatus of the type described comprising, in combination, a wire-head having inlet and drainage oritices controlled respectively by electromagnetically-actuated valves, means or supplying to said inlet orice under pressure a stream of dilute paper stock flowing from the rililers of a paper mill, a stand-pipe located to one side of and some what below the wire-head to receive the discharge therefrom and having a drainage oritice controlled by an electromagneticallyactuated valve, a pressure recorder operatively associated with the stand-pipe, a shower-head located over the wire-head and having a water inlet oriiice controlled by an electromagnetically-actuated valve, electric circuits or said electromagnetically-actuated valves, and control means lor the electric circuits including timing mechanism operative during successive predetermined time intervals to close and for a fraction of each time interval to maintain open the actuating circuits of the valves controlling the inlet oriice or' the wirehead and the drainage orilices or' the wirehead and stand-pipe and then to open and maintain open said circuits during the remainder of the time interval and shortly after the opening of said circuits to close and maintain closed for another fraction of each time interval the actuating circuit of the valve controlling the water inlet orifice of the shower-head and then to open and maintain open said circuit during the remainder of the time interval.

16. ln apparatus of the type described, the combination, with a wire-head having inlet and drainage orifices controlled respectively by normally closed and normally open electromagnetically-actuated valves, a standpipe to receive the dischargejrom the wirehead having a drainage orifice controlled by a normally open electromagnetically-actuated valve, and a shower-head for washing out the wire-head and standpipe having a water inlet orice controlled by a normally closed electromagnetically-actuated valve, of a switch-controlled electric circuit for simultaneously energizing the magnet coils of the valves controlling the inlet an-d drainage orifices of the wire-head and the drainage orifice of the stand-pipe, a second switchcontrolled electric circuit for energizing the magnet coil of the valve controlling the water inlet oriice of the shower-head,

and a timing device for controlling the switches of the said two electric circuits comprising two cams mounted to rotate together at slow speed and having each an active cam facel extending through a substantial arc of a circle and operative the active face of one cam to actuate the switch controlling the electric circuit of the magnets of the valves of the wire-head and stand-pipe andthe active face of the second cam set slightly behind that of the iirst cam, to actuate the switch controlling the electric circuit of the magnet of the valve of the shower-head.

GEORGE F. FRENCH. 

